| ObjectionAt physiological condition,we observed the morphological characteristics of LA and PV,and measured the correlated distance,and investigated the relationship of anatomic structure,and abtained accurate anatomic structure data so as to provide basis for AF and its RFCA.MethodsA 64-MSCT scanner was used for coronary imaging.Contiguous multiphase images were generated from axial MSCT data and semi-automated 3D segmentation technique was applied to generate LA and PV.Each subject lay on the scanner table in the supine position.Oral B-blocker 12.5-25mg was administered to the person whose heart rate over 70 before data acquisition to lower the heart rate for improved relative temporal resolution,which in turn enabled image production with fewer artifacts due to motion.ECG-gated enhanced 64-slice CT was performed with a slice thickness of 0.4 mm,a gantry rotation speed of 350 ms per rotation,and a tube voltage of 120 kV.The tube current was increased up to 750 millamperes(mA)only in 35-80%of the R-to-R interval of the ECG,Contrast material was administered via a 20-gauge needle into the cubital vein and this volume was then injected at a rate of 2.5-3.5 ml/s,CT scanning was then performed with retrospective ECG-gated reconstruction.we obtain maxium-intensity-projection images at the workstation.these allow a more accurate measurement of the ostial diameter of pulmonary veins obliquely oriented to the axial imaging plane.86 continuous persons without pulmonary and cardiac disease(46 males,age 54±13 years 40 females,age 58±11 years)were studied retrospectively by 64-MSCT scans for anatomical criteria regarding left atrial appendage(LAA),mitral annulus(MA),left superior pulmonary vein (LSPV),left inferior pulmonary vein(LIPV),right superior pulmonary vein (RSPV),right inferior pulmonary vein(RIPV),right middie pulmonary vein (RMPV)were measured and analysed by two thoracic radiologists respectively. Different anatomical correlations were demonstrated minimum distance of LSPV-RSPVmin,LIPV-MAmin,LIPV-LAAmin,LIPV-RIPVmin,LAA-MAmin,LSPV-LI PVmin,LSPV-LAAmin,RSPV-RIPVmin,RIPV-RMPVmin,RSPV-RMPVmin.ResultsFour pulmonary veins compose the common pulmonary vein anatomy.however, pulmonary vein anatomy is commonly variable,such as common ostia or extra veins.A common PV occurred frequently on the left pulmonary vein and three branchs on the right pulmonary vein respectively:12/86 and 17/86.LSPV-LAAmin:3.6±1.3mm,LIPV-LAAmin:5.9±2.1mm,LSPV-RSPVmin:31.4±9.8mm,LAA-MAmin:10.6±0.28mm,LIPV-RIPVmin:32.5±10.2mm,LSPVLIPVmin: 5.7±2.3mm,LIPV-MAmin:21.1±4.1mm,RSPV-RIPVmin:5.8±2.2mm, RMPV-RSPVmin:3.1±1.8mm,RMPV-RIPVmin:3.0±1.6mm,LSPV-LAAmin and LIPV-LAAmin(p＜0.05 n=80),There was no significant with RMPV-RSPVmin and RMPV-RIPVmin(p＜0.05 n=17).ConclusionAssessment of images of LA and PV by MSCT is available,which conduces to doctors to be familiar with anatomic structure.Penetrating apprehension is essential before RFCA.Exact measurements of all structures and its anatomic correlations are possible with MSCT,which allows pre-interventional planning and provides anatomic basis for RFCA of AF. |
